diff --git a/sdk/cosmos/azure-cosmos/CHANGELOG.md b/sdk/cosmos/azure-cosmos/CHANGELOG.md
index 4017eee05c8a..825e2d909a9b 100644
--- a/sdk/cosmos/azure-cosmos/CHANGELOG.md
+++ b/sdk/cosmos/azure-cosmos/CHANGELOG.md
@@ -3,10 +3,12 @@
 ### 4.6.1 (Unreleased)
 
 #### Features Added
+* Added support for using the start time option for change feed pulls. See [PR 34694](https://github.com/Azure/azure-sdk-for-python/pull/34694)
 
 #### Breaking Changes
 
 #### Bugs Fixed
+* Fixed bug where change feed pulls in Async clients weren't returning all pages. See [PR 34694](https://github.com/Azure/azure-sdk-for-python/pull/34694)
 
 #### Other Changes
 
diff --git a/sdk/cosmos/azure-cosmos/README.md b/sdk/cosmos/azure-cosmos/README.md
index 4bd8666c682b..f34d2d3df0b2 100644
--- a/sdk/cosmos/azure-cosmos/README.md
+++ b/sdk/cosmos/azure-cosmos/README.md
@@ -158,7 +158,6 @@ Currently, the features below are **not supported**. For alternatives options, c
 Streamable queries like `SELECT * FROM WHERE` *do* support continuation tokens.
 * Change Feed: Processor
 * Change Feed: Read multiple partitions key values
-* Change Feed: Read specific time
 * Cross-partition ORDER BY for mixed types
 * Enabling diagnostics for async query-type methods
 
diff --git a/sdk/cosmos/azure-cosmos/azure/cosmos/_base.py b/sdk/cosmos/azure-cosmos/azure/cosmos/_base.py
index f8ab0ca15961..d6b64a758648 100644
--- a/sdk/cosmos/azure-cosmos/azure/cosmos/_base.py
+++ b/sdk/cosmos/azure-cosmos/azure/cosmos/_base.py
@@ -23,6 +23,7 @@
 """
 
 import base64
+from datetime import timezone, datetime
 from email.utils import formatdate
 import json
 import uuid
@@ -291,8 +292,17 @@ def GetHeaders(  # pylint: disable=too-many-statements,too-many-branches
             if_none_match_value = options["continuation"]
         elif options.get("isStartFromBeginning") and not options["isStartFromBeginning"]:
             if_none_match_value = "*"
+        elif options.get("startTime"):
+            dt = options.get("startTime")
+            # If datetime has specified timezone, and it's not utc, convert to utc.
+            # Otherwise, assume it is in UTC.
+            if isinstance(dt, datetime):
+                if dt.tzinfo is not None and dt.tzinfo.utcoffset(dt) is not None:
+                    dt = dt.astimezone(timezone.utc)
+                headers[http_constants.HttpHeaders.IfModified_since] = dt.strftime('%a, %d %b %Y %H:%M:%S GMT')
         if if_none_match_value:
             headers[http_constants.HttpHeaders.IfNoneMatch] = if_none_match_value
+
         headers[http_constants.HttpHeaders.AIM] = http_constants.HttpHeaders.IncrementalFeedHeaderValue
     else:
         if options.get("continuation"):
diff --git a/sdk/cosmos/azure-cosmos/azure/cosmos/_execution_context/aio/base_execution_context.py b/sdk/cosmos/azure-cosmos/azure/cosmos/_execution_context/aio/base_execution_context.py
index 3f52e342d641..c8e13940ed5d 100644
--- a/sdk/cosmos/azure-cosmos/azure/cosmos/_execution_context/aio/base_execution_context.py
+++ b/sdk/cosmos/azure-cosmos/azure/cosmos/_execution_context/aio/base_execution_context.py
@@ -119,11 +119,15 @@ async def _fetch_items_helper_no_retries(self, fetch_function):
         fetched_items = []
         # Continues pages till finds a non-empty page or all results are exhausted
         while self._continuation or not self._has_started:
+            # Check if this is first fetch for read from specific time change feed.
+            # For read specific time the first fetch will return empty even if we have more pages.
+            is_s_time_first_fetch = self._is_change_feed and self._options.get("startTime") and not self._has_started
             if not self._has_started:
                 self._has_started = True
             new_options = copy.deepcopy(self._options)
             new_options["continuation"] = self._continuation
 
+            response_headers = {}
             (fetched_items, response_headers) = await fetch_function(new_options)
             continuation_key = http_constants.HttpHeaders.Continuation
             # Use Etag as continuation token for change feed queries.
@@ -131,7 +135,8 @@ async def _fetch_items_helper_no_retries(self, fetch_function):
                 continuation_key = http_constants.HttpHeaders.ETag
             # In change feed queries, the continuation token is always populated. The hasNext() test is whether
             # there is any items in the response or not.
-            if not self._is_change_feed or fetched_items:
+            # For start time however we get no initial results, so we need to pass continuation token
+            if not self._is_change_feed or fetched_items or is_s_time_first_fetch:
                 self._continuation = response_headers.get(continuation_key)
             else:
                 self._continuation = None
diff --git a/sdk/cosmos/azure-cosmos/azure/cosmos/_execution_context/base_execution_context.py b/sdk/cosmos/azure-cosmos/azure/cosmos/_execution_context/base_execution_context.py
index f0769f6caf25..8eddb72e3f80 100644
--- a/sdk/cosmos/azure-cosmos/azure/cosmos/_execution_context/base_execution_context.py
+++ b/sdk/cosmos/azure-cosmos/azure/cosmos/_execution_context/base_execution_context.py
@@ -117,11 +117,15 @@ def _fetch_items_helper_no_retries(self, fetch_function):
         fetched_items = []
         # Continues pages till finds a non-empty page or all results are exhausted
         while self._continuation or not self._has_started:
+            # Check if this is first fetch for read from specific time change feed.
+            # For read specific time the first fetch will return empty even if we have more pages.
+            is_s_time_first_fetch = self._is_change_feed and self._options.get("startTime") and not self._has_started
             if not self._has_started:
                 self._has_started = True
             new_options = copy.deepcopy(self._options)
             new_options["continuation"] = self._continuation
 
+            response_headers = {}
             (fetched_items, response_headers) = fetch_function(new_options)
             continuation_key = http_constants.HttpHeaders.Continuation
             # Use Etag as continuation token for change feed queries.
@@ -129,7 +133,8 @@ def _fetch_items_helper_no_retries(self, fetch_function):
                 continuation_key = http_constants.HttpHeaders.ETag
             # In change feed queries, the continuation token is always populated. The hasNext() test is whether
             # there is any items in the response or not.
-            if not self._is_change_feed or fetched_items:
+            # For start time however we get no initial results, so we need to pass continuation token
+            if not self._is_change_feed or fetched_items or is_s_time_first_fetch:
                 self._continuation = response_headers.get(continuation_key)
             else:
                 self._continuation = None
diff --git a/sdk/cosmos/azure-cosmos/azure/cosmos/_synchronized_request.py b/sdk/cosmos/azure-cosmos/azure/cosmos/_synchronized_request.py
index 7dea1f2abec4..5663b8aa9faa 100644
--- a/sdk/cosmos/azure-cosmos/azure/cosmos/_synchronized_request.py
+++ b/sdk/cosmos/azure-cosmos/azure/cosmos/_synchronized_request.py
@@ -21,7 +21,7 @@
 
 """Synchronized request in the Azure Cosmos database service.
 """
-
+import copy
 import json
 import time
 
@@ -139,7 +139,7 @@ def _Request(global_endpoint_manager, request_params, connection_policy, pipelin
         )
 
     response = response.http_response
-    headers = dict(response.headers)
+    headers = copy.copy(response.headers)
 
     data = response.body()
     if data:
diff --git a/sdk/cosmos/azure-cosmos/azure/cosmos/aio/_asynchronous_request.py b/sdk/cosmos/azure-cosmos/azure/cosmos/aio/_asynchronous_request.py
index a3e8b25a823c..176b33807ddd 100644
--- a/sdk/cosmos/azure-cosmos/azure/cosmos/aio/_asynchronous_request.py
+++ b/sdk/cosmos/azure-cosmos/azure/cosmos/aio/_asynchronous_request.py
@@ -21,7 +21,7 @@
 
 """Asynchronous request in the Azure Cosmos database service.
 """
-
+import copy
 import json
 import time
 
@@ -107,7 +107,7 @@ async def _Request(global_endpoint_manager, request_params, connection_policy, p
         )
 
     response = response.http_response
-    headers = dict(response.headers)
+    headers = copy.copy(response.headers)
 
     data = response.body()
     if data:
diff --git a/sdk/cosmos/azure-cosmos/azure/cosmos/aio/_container.py b/sdk/cosmos/azure-cosmos/azure/cosmos/aio/_container.py
index eebd6c552c64..7de7662c5ad1 100644
--- a/sdk/cosmos/azure-cosmos/azure/cosmos/aio/_container.py
+++ b/sdk/cosmos/azure-cosmos/azure/cosmos/aio/_container.py
@@ -21,7 +21,7 @@
 
 """Create, read, update and delete items in the Azure Cosmos DB SQL API service.
 """
-
+from datetime import datetime
 from typing import Any, Dict, Mapping, Optional, Sequence, Type, Union, List, Tuple, cast
 from typing_extensions import Literal
 
@@ -476,6 +476,7 @@ def query_items_change_feed(
         *,
         partition_key_range_id: Optional[str] = None,
         is_start_from_beginning: bool = False,
+        start_time: Optional[datetime] = None,
         continuation: Optional[str] = None,
         max_item_count: Optional[int] = None,
         partition_key: Optional[PartitionKeyType] = None,
@@ -486,6 +487,9 @@ def query_items_change_feed(
 
         :keyword bool is_start_from_beginning: Get whether change feed should start from
             beginning (true) or from current (false). By default, it's start from current (false).
+        :keyword datetime start_time: Specifies a point of time to start change feed. Start time in
+            http://www.ietf.org/rfc/rfc2616.txt format. Converts datetime to UTC if timezone is defined. Assumes
+            datetime is in UTC if timezone is not defined.
         :keyword str partition_key_range_id: ChangeFeed requests can be executed against specific partition key
             ranges. This is used to process the change feed in parallel across multiple consumers.
         :keyword str continuation: e_tag value to be used as continuation for reading change feed.
@@ -505,6 +509,7 @@ def query_items_change_feed(
             kwargs['priority'] = priority
         feed_options = _build_options(kwargs)
         feed_options["isStartFromBeginning"] = is_start_from_beginning
+        feed_options["startTime"] = start_time
         if partition_key_range_id is not None:
             feed_options["partitionKeyRangeId"] = partition_key_range_id
         if partition_key is not None:
diff --git a/sdk/cosmos/azure-cosmos/azure/cosmos/container.py b/sdk/cosmos/azure-cosmos/azure/cosmos/container.py
index 1262d96c7327..400735a28906 100644
--- a/sdk/cosmos/azure-cosmos/azure/cosmos/container.py
+++ b/sdk/cosmos/azure-cosmos/azure/cosmos/container.py
@@ -21,7 +21,7 @@
 
 """Create, read, update and delete items in the Azure Cosmos DB SQL API service.
 """
-
+from datetime import datetime
 import warnings
 from typing import Any, Dict, List, Optional, Sequence, Union, Tuple, Mapping, Type, cast
 from typing_extensions import Literal
@@ -307,6 +307,7 @@ def query_items_change_feed(
         self,
         partition_key_range_id: Optional[str] = None,
         is_start_from_beginning: bool = False,
+        start_time: Optional[datetime] = None,
         continuation: Optional[str] = None,
         max_item_count: Optional[int] = None,
         *,
@@ -320,6 +321,9 @@ def query_items_change_feed(
             This is used to process the change feed in parallel across multiple consumers.
         :param bool is_start_from_beginning: Get whether change feed should start from
             beginning (true) or from current (false). By default, it's start from current (false).
+        :param datetime start_time: Specifies a point of time to start change feed. Start time in
+            http://www.ietf.org/rfc/rfc2616.txt format. Converts datetime to UTC if timezone is defined. Assumes
+            datetime is in UTC if timezone is not defined.
         :param max_item_count: Max number of items to be returned in the enumeration operation.
         :param str continuation: e_tag value to be used as continuation for reading change feed.
         :param int max_item_count: Max number of items to be returned in the enumeration operation.
@@ -342,6 +346,8 @@ def query_items_change_feed(
             feed_options["partitionKey"] = self._set_partition_key(partition_key)
         if is_start_from_beginning is not None:
             feed_options["isStartFromBeginning"] = is_start_from_beginning
+        if start_time is not None and is_start_from_beginning is False:
+            feed_options["startTime"] = start_time
         if max_item_count is not None:
             feed_options["maxItemCount"] = max_item_count
         if continuation is not None:
diff --git a/sdk/cosmos/azure-cosmos/test/test_query.py b/sdk/cosmos/azure-cosmos/test/test_query.py
index 4d1acfee34c0..8120ee0084dc 100644
--- a/sdk/cosmos/azure-cosmos/test/test_query.py
+++ b/sdk/cosmos/azure-cosmos/test/test_query.py
@@ -3,7 +3,8 @@
 
 import unittest
 import uuid
-
+from datetime import datetime, timedelta
+from time import sleep
 import pytest
 
 import azure.cosmos._retry_utility as retry_utility
@@ -278,6 +279,72 @@ def test_query_change_feed_with_pk_range_id(self):
         self.assertEqual(len(iter_list), 0)
         self.created_db.delete_container(created_collection.id)
 
+    def test_query_change_feed_with_start_time(self):
+        created_collection = self.created_db.create_container_if_not_exists("query_change_feed_start_time_test",
+                                                                            PartitionKey(path="/pk"))
+        batchSize = 50
+
+        def round_time():
+            utc_now = datetime.utcnow()
+            return utc_now - timedelta(microseconds=utc_now.microsecond)
+        def create_random_items(container, batch_size):
+            for _ in range(batch_size):
+                # Generate a Random partition key
+                partition_key = 'pk' + str(uuid.uuid4())
+
+                # Generate a random item
+                item = {
+                    'id': 'item' + str(uuid.uuid4()),
+                    'partitionKey': partition_key,
+                    'content': 'This is some random content',
+                }
+
+                try:
+                    # Create the item in the container
+                    container.upsert_item(item)
+                except exceptions.CosmosHttpResponseError as e:
+                    self.fail(e)
+
+        # Create first batch of random items
+        create_random_items(created_collection, batchSize)
+
+        # wait for 1 second and record the time, then wait another second
+        sleep(1)
+        start_time = round_time()
+        sleep(1)
+
+        # now create another batch of items
+        create_random_items(created_collection, batchSize)
+
+        # now query change feed based on start time
+        change_feed_iter = list(created_collection.query_items_change_feed(start_time=start_time))
+        totalCount = len(change_feed_iter)
+
+        # now check if the number of items that were changed match the batch size
+        self.assertEqual(totalCount, batchSize)
+
+        # negative test: pass in a valid time in the future
+        future_time = start_time + timedelta(hours=1)
+        change_feed_iter = list(created_collection.query_items_change_feed(start_time=future_time))
+        totalCount = len(change_feed_iter)
+        # A future time should return 0
+        self.assertEqual(totalCount, 0)
+
+        # test a date that is not utc, will ignore start time option
+        not_utc_time = datetime.now()
+        change_feed_iter = list(created_collection.query_items_change_feed(start_time=not_utc_time))
+        totalCount = len(change_feed_iter)
+        # should return 100 (double the batch size)
+        self.assertEqual(totalCount, batchSize*2)
+
+        # test an invalid value, will ignore start time option
+        invalid_time = "Invalid value"
+        change_feed_iter = list(created_collection.query_items_change_feed(start_time=invalid_time))
+        totalCount = len(change_feed_iter)
+        # should return 100 (double the batch size)
+        self.assertEqual(totalCount, batchSize * 2)
+
+
     def test_populate_query_metrics(self):
         created_collection = self.created_db.create_container("query_metrics_test",
                                                               PartitionKey(path="/pk"))
diff --git a/sdk/cosmos/azure-cosmos/test/test_query_async.py b/sdk/cosmos/azure-cosmos/test/test_query_async.py
index 3258de2343b1..6acdbb462845 100644
--- a/sdk/cosmos/azure-cosmos/test/test_query_async.py
+++ b/sdk/cosmos/azure-cosmos/test/test_query_async.py
@@ -3,6 +3,8 @@
 
 import unittest
 import uuid
+from asyncio import sleep
+from datetime import datetime, timedelta
 
 import pytest
 
@@ -316,8 +318,76 @@ async def test_query_change_feed_with_pk_range_id_async(self):
         iter_list = [item async for item in query_iterable]
         assert len(iter_list) == 0
 
+    @pytest.mark.asyncio
+    async def test_query_change_feed_with_start_time(self):
+        created_collection = await self.created_db.create_container_if_not_exists("query_change_feed_start_time_test",
+                                                                            PartitionKey(path="/pk"))
+        batchSize = 50
+
+        def round_time():
+            utc_now = datetime.utcnow()
+            return utc_now - timedelta(microseconds=utc_now.microsecond)
+
+        async def create_random_items(container, batch_size):
+            for _ in range(batch_size):
+                # Generate a Random partition key
+                partition_key = 'pk' + str(uuid.uuid4())
+
+                # Generate a random item
+                item = {
+                    'id': 'item' + str(uuid.uuid4()),
+                    'partitionKey': partition_key,
+                    'content': 'This is some random content',
+                }
+
+                try:
+                    # Create the item in the container
+                    await container.upsert_item(item)
+                except exceptions.CosmosHttpResponseError as e:
+                    pytest.fail(e)
+
+        # Create first batch of random items
+        await create_random_items(created_collection, batchSize)
+
+        # wait for 1 second and record the time, then wait another second
+        await sleep(1)
+        start_time = round_time()
+        await sleep(1)
+
+        # now create another batch of items
+        await create_random_items(created_collection, batchSize)
+
+        # now query change feed based on start time
+        change_feed_iter = [i async for i in created_collection.query_items_change_feed(start_time=start_time)]
+        totalCount = len(change_feed_iter)
+
+        # now check if the number of items that were changed match the batch size
+        assert totalCount == batchSize
+
+        # negative test: pass in a valid time in the future
+        future_time = start_time + timedelta(hours=1)
+        change_feed_iter = [i async for i in created_collection.query_items_change_feed(start_time=future_time)]
+        totalCount = len(change_feed_iter)
+        # A future time should return 0
+        assert totalCount == 0
+
+        # test a date that is not utc, will ignore start time option
+        not_utc_time = datetime.now()
+        change_feed_iter = [i async for i in created_collection.query_items_change_feed(start_time=not_utc_time)]
+        totalCount = len(change_feed_iter)
+        # should return 100 (double the batch size)
+        assert totalCount == batchSize * 2
+
+        # test an invalid value, will ignore start time option
+        invalid_time = "Invalid value"
+        change_feed_iter = [i async for i in created_collection.query_items_change_feed(start_time=invalid_time)]
+        totalCount = len(change_feed_iter)
+        # should return 100 (double the batch size)
+        assert totalCount == batchSize * 2
+
         await self.created_db.delete_container(created_collection.id)
 
+    @pytest.mark.asyncio
     async def test_populate_query_metrics_async(self):
         created_collection = await self.created_db.create_container(
             "query_metrics_test" + str(uuid.uuid4()),